Mechanical oscillator mechanisms for timepieces, including a balance spring, generally include a balance spring stud for attaching the outer end of the balance spring.
The attachment of the balance spring to the stud is generally achieved by adhesive bonding, which is not perfectly reproducible, and may result in contamination of the timepiece movement.
CH Patent Application No 317531A in the name of EBAUCHES BETTLACH SA describes a balance spring stud with a slot, made of a plastically deformable material for permanently attaching the stud and the balance spring.
EP Patent Application No 1580625A1 in the name of ASULAB SA describes the attachment of a lifting-piece in a pallet lever housing; the portion including this housing is made of a shape memory alloy capable of undergoing a reversible transformation between an austenitic phase and a martensitic phase.